DESCRIPTION (Applicant's Description): EBV-related lymphoproliferative states and lymphomas are important clinical entities in normal and immunocompromised human hosts. Epstein-Barr nuclear antigen 2 (EBNA2), a latently expressed viral nuclear protein, mediates specific cellular and viral gene activation that is required for EBV transformation and immortalization of B-lymphocytes. Dr. Daniel Y. Wu has shown that EBNA2 exerts its transactivating function by engaging cellular transcription factors include hSNF/SWI complex. This proposed work aims to define the function of the EBNA2-Ini1 interaction by establishing reversible and conditional repression of the Ini1 gene with targeted ribozyme. Dr. Wu will determine the effects of Ini-1 ablation on EBNA2 mediated gene activation and EBV-induced B-cell immortalization. In a complementary set of experiments, he will determine whether EBNA2 mutants that fail to bind Ini1 affect the same functions. The reverse genetic methodologies that he proposes to develop will apply to investigations of other lymphocyte genes. The present project is a part of an ongoing effort in the laboratory of Dr. William H. Schubach, Dr, Wu's mentor, to study the mechanism of EBV mediated B-lymphocyte immortalization. Dr. Wu's goal is to develop a career in studying oncogenesis and identifying potential gene therapy targets and approaches. The MCSDA will provide the retraining needed to bridge his molecular genetics background and develop an independent career in molecular medicine. Dr. Schubach, who combines breadth in cancer and expertise in molecular biology, will continue to provide scientific and career guidance and will be joined in this effort by Dr. Mark Groudine.